Scanning drum construction



March 29, 1938. A, Z|| GER 2,112,390

SCANNING DRUM CONSTRUCTION Filed Nov. 28, 1934 2 Sheets-Sheet l ATTORN EY5 `Nlarch 29, 1938. A ZlLLGER 2,112,390

SCANNING DRUM CONSTRUCTION Filed Nov. 28, 1954 2 Sheets-Sheet 2 xNvENToR /IfP/v Z/LL 65AD ATTORNEYS Patented Mar. 29, 193s 2,112,390` t UNITED STATES PATENT OFFICE SCANNING DRUM CONSTRUCTION Arno Zillger, Narberth, Pa., assignor to National Television Corporation, Wilmington, Del., a corporation of Delaware Application ANovember 28, 1934, Serial No. '755,112

9 Claims. (Cl. 178-7.6)

This invention relates to television apparatus rotated and the surfaces make one complete roand particularly to a scanning drum for such tation around the drum. It is dicult to mount apparatus. f these plates upon a shaft with accurate angular One of the objects of the invention is to pro- Spacing as the slightest change in angularity of y vide a helical mirror drum for television scanning a single plate Will cause one line of the picture 5k which is light in Weight, compact, and easy to to be moved sidewise so that it disturbs the acconstruct'and assemble. curacy of the picture. 'I'he present invention Another object of the invention is to provide a provides a very simple method of mounting these television scanning drum in which the individual plates so that they may be assembled with great mirror surfaces forming the drum may be accuaccuracy. l0

ratelypositioned with respect to each other. Referring tothe drawings a plurality of trian- A further object of the invention is to provide gular plates I0 are shown, each having a hole I I. a simple construction for a television drum by in the center thereof which is adapted to t over which the individual units for building up drums a hollow sleeve I2 with a snug iit, so that the l5 to scan different numbers of lines in a picture plates are all centered upon the sleeve. The 15 may be stamped out with the same dies. sleevey I2 may be provided with a dished flangev A still further object of the invention is to pro- I3 at the lower end thereof provided with a hub vide a television drum construction in which I4 to lit over the end of thesleeve and aV supdrums for scanning several different numbers of porting disc I5 for the plates. The disc I5 andA lines may be built up with the same units. the flange I3 may be Welded together and tothe 20 Other objects and objects relating particularly lower end of the sleeve. The proper number of to the construction and assembly of the various plates are mounted -on the sleeve in a manner parts will be apparent as the description of the to be hereinafter described and a second supinvention proceeds. porting disc I6 and flange. I'I are mo-unted at the The invention is illustrated in the accompanyupper end of the sleeve to prevent axial move- 25 ing drawings, in which: ment of the plates on the sleeve, the flange Il Fig. l is an elevational view partly in section being provided with a suitable hub I8 for Weldof a completed drum for scanning a 60 line picing to the upper end of the sleeve. When the plates are positioned on the sleeve and the flange ture: Fig. 2 is a sectional plan view of the drum is Welded iny place the drum becomesa singleunit 30 taken on the line 2-2 Vof Fig. 1; for mounting on a suitable motor shaft.

Fig. 3 is a sectional elevational view of a por- In order tomount the drum on a shaft I protion of the plates of the drum taken on the curved vide a disc I9 in the lower end of the sleeve which line 3 3 of Fig. 2; may be secured in place by fingers 20. onthe end.

Fig. lis a plan View of one of the plates used of the sleeve which are bent o-ver the disc. v'I'he 35 in the drum construction; disc is as large as the outer diameter of the sleeve Fig. 5 is a plan view of two of the plates showso that it fits upon the end thereof, and is pro,- ing the zianner of spacing for a 60 line picture; vided with notches 2| to receive the fingers 20. Fig. 6 is a plan View of a pair of plates show- 'Ihe center of the disc may be provided with a ing them spaced for a 120 line picture; suitable hubbed opening 22 to t upon a motor 40 Fig. 7 is a plan view ofra pair of plates spaced shaft. In the present illustration a motor- 23 is for a 240 line picture; I shown having a shaft 24 upon which the drum is Fig. 8r is a sectional elevational view through mounted. If desired this shaft may have a the plates of Fig. 5 taken on the line 8-8 of that shoulder 25 upon which the disc I9 rests. figure; and In .like manner a second disc 26 is provided at 45 Fig. 9 is a sectional elevational view of a modithe top of the drum, fitting on the top of the fied form of drum. construction. sleeve I2 in the same manner as the other disc The invention relates particularly to that type and provided with notches 28 in which the finof drum shown and described. in my Patent No. gers 29, attached tothe sleeves, may fit. 'Ihese 2,077,866, of April 20, 1937, andy comprising a plufingers are bentover the top of the disc to hold 5,0 rality of plates mounted in stacked relation upon it securely in position. 'I'he disc 26 is also proa shaft. One edge of each. plate is mirrored and vided with a hubbed center opening 30 to fit on the plates are spaced at equal angles around the the top of the shaft 24 and the t of both the circumference ofthe drum so that they pass in discs I9 and 26 upon the shaft should be snugso front of the observer in succession as the drum is as to prevent movement of the drum upon the 55 shaft. The shaft has a threaded outer end 3| and a washer 32 may be placed over the disc 26 accompanied by a lock washer 33, while a nut 34 may be threaded on to the shaft to hold the drum securely in position. When the nut is drawn up tight the drum will turn with the shaft.

In Fig. 4 one of the triangular plates I0 is illustrated in detail with the spacing holes shown in the corners thereof. Ihese plates may be made of any suitable material which is capable of retaining a high polish and in the present instance I may prefer to make them out of duralumin. I preferably make them in the form of equilateral triangles so as to distribute the weight symmetrically around the shaft. For convenience the corners of the triangular plates have been lettered A, B and C. At corner A I provide two spacing holes and at corners B and C I provide one each. These holes are positioned preferably as far as possible from the center of the plate without getting too close to the side edges and have their centers equidistant from the center of the plate. The holes are positioned with respect to lines drawn through the corner and the exact center of the plate. The hole 35 in the corner A has its cent-er positioned at 3 degrees from the center line of the corner in a counterclockwise direction, while the hole 36 in the corner A is positioned at 41/2 degrees in a clockwise direction from the corner line. In corner B the hole 31 is positioned 3 degrees from the corner line in a clockwise direction, while in corner C the hole 38 is positioned directly on the center line. i

'I'he plate may also be provided with additional holes 39 for the purpose of lightening the drums. These should be spaced symmetrically about the center so as to equally distribute the weight and may be as large andas numerous as desired as long as the edges of the plates are not weakened. In Figs. 5, 6, and 7 these holes have not been shown to avoid confusion.

In assembling a series of these plates let it first be assumed that a 60 line picture is desired. Sixty of the plates will then be stacked as in the showing of Figs. 1 and 2 with a spacing of 6 degrees between adjacent plates so that the drum will make a complete scanning in one rotation. In order to obtain a spacing of 6 degrees for the plates I position one plate, as for instance the plate 40 in Fig. 5, upon the sleeve l2 with the corner A uppermost, as indicated, and the corners B and C at the right and left respectively. I then position a second plate on top of the first plate with the corner A rotated through 126 degrees in a clockwise direction. This brings the corner A of the second plate 4|, 6 degrees beyond the corner B of the first plate, and since the hole 31 in the corner B of the rst plate 40 is 3 degrees from the corner line in a clockwise direction and the hole 35 in the corner A of the second plate 4| is 3 degrees from the corner line in a counterclockwise direction the 6 degree spacing of the corners of the two plates will make these two holes fall in alignment and a pin 42 may be inserted in the holes to secure the plates. together. All of the other spacing holes will be out of alignment. A third plate, (not shown), is then placed upon the second plate with its corner A over the corner B of the second plate whereupon the hole 31 in that corner of the second plate will align with the hole 35 in the corner A of the third plate so that another pin may be inserted to hold the second and third plates together. The pins 42 are just long enough to equal a little less than the thickness of two plates so that the rst pin spaces the rst two plates while the second spaces the second and third and additional plates are then placed on the sleeve in the same manner until they have all been properly spaced thereon.

While the triangular plates hav-e three sides it will be evident that only one side of each plate is used for the reflecting surfaces. If we assume the surface between corners A and By to be the reflecting surface of the first plate then the second upper plate 4| will have the surface between the corners C and A as the reflecting surface and the third plate will have the surface between the corners B and C as the reflecting surface. All of the plates, therefore, do not have the same reflecting surfaces but every third plate in the stack is alike. This separates the plates into three groups of plates, and all of the plates for one drum may be ground and polished, or otherwise treated to form the reflecting surfaces, at the same time. Thus a stack of plates may be mounted together so that 20 plates have their surfaces A-B aligned together and also aligned with the surfaces C-A of a second group of 20 and also with the surfaces C-B of a third group of 20. Held in one block with all of these surfaces aligned they may be ground and polished as desired and assembled later with proper spacing.

If it is desired to make a drum having 120 lines, 120 plates are used spaced about the circumference of the drum at an angleV of 3 degrees apart. Each of these plates will be exactly the same as the plate l0 shown in Fig. 4 but will be half as thick and twice as many are put on the same size drum. In order to get the spacing of 3 degrees the arrangement of Fig. 6 is resorted to. A plate 43 is placed on the drum sleeve with the corner A at the lower left hand side, the corner B at the top and the corner C at the lower right hand side. Then the second plate 44 is placed on top of it but rotated through 117 degrees in a counterclockwise direction. Inasrnuch as the hole 38 in the corner C of the plate 43 is on the corner line and the hole 35 in the corner A of the second plate is 3 degrees in a counterclockwise direction from the corner line, as indicated in Fig. 4, and the plates are 3 degrees separated, these two holes will align and one of the pins 42 may be inserted through the two plates holding them in position. However the hole 31 in the corner B of the plate 43 is also 3 degrees from the corner line in a clockwise direction so that it comes into alignment with the hole 38 in the corner C of the second plate 44 and another of the pins 42 may also be used in this corner if desired. In like manner the third' plate is added with its corner A moved through 117 degrees in a counterclockwise direction from the corner A of the second plate and the holes 35 and 38 of the third plate will align with the holes 38 and 31 respectively of the second plate.

In this case also the reflecting edge is the same for every third plate and hence the reflecting edges may be formed on the plates as indicated above with the plates arranged in three groups.

If a picture of 240 lines is desired 240 plates are required and these plates may be exactly the same as the plate l0 of Fig. 4 except that they will be 1A as thick. In arranging the plates on the sleeve the first plate 45 may be positioned just as in Fig. 4 with the corner A at the lower right hand side, the corner B at the left hand side, and the corner C at the top. The second plate is then placed in position rotated in a counterclockwise direction through 1181/2 degrees. This places theoorner B ofthe second plate over the corner A ofthe rst plate with a spacing of 11/2 degrees between the two, and inasmuch as the hole 36 in thelcorner A of the plate 45 is spaced l1/2 degrees from the corner line in a counterclockwise direction and the hole 31 in the corner B of the plate 46 is spaced 3 degrees from the corner line in the same direction these two holes will line up and one of the pins 42 may be used to secure them in this position. The third plate is then positioned over the second with the corner B adjacent the corner A of the second and the holes 31 and 36 in the third and second plates respectively in alignment to receive `another' of the pins 42. In this arrangement also it will be noted that the reflecting surface falls on the same side for every third plate so that these plates may be treated to give them reflecting surfaces in groups of three.

From the above description it will be evident that I have provided a plate for a scanning drum which may be stamped out with a suitable die and is so formed that it can be used for several different angular spacings. While I have described each of these spacings as requiring a different thickness plate they may be all'of one thickness if desired so that the plates for the 60, 120 or 240 line drum. may be mad-e from the same stock. If this is done the plates will all correspond in thickness to the 240 line plate which is 1/4 of the thickness of the plates shown in Figs. 1, 3 and 8. One -plate for each line will then be used for the 240 line drum, two plates for each line will be used for the 120 line drum and four plates for each line will be used for the 60 line drum. Where a plurality of plates are used for one line the effect will be the same as if one plate were used as long as the reflecting surfaces are accurate and are aligned together. Also it will be understood that the corners A of the several plates making one line of the picture will be aligned together so that the pins 42 will pass through all of the plates forming two lines of the picture, or the equivalent of two plates if a single plate is used for each line.

The arrangement lends itself to very economical construction of a drum for scanning pictures of different numbers of lines as it permits the stamping of all of the plates with the same set of dies and if desired out of the same thickness stock. The edges of the plates which are not used for the reflecting surface may be blackened or otherwise made non-reflecting as by beveling so that they will not pick up light from the linear light source. v

A modified form of the drum construction is shown in Fig. 9. In this arrangement the parts may be die cast and the combination of parts has the advantage among others that the motor shaft may be shorter than the construction of Fig. 1.

A hub 41 of aluminum or other light metal is provided with a plate supporting flange 48 which has a fiat upper surface 49 upon which the stack of plates may rest. A sleeve 50 may be attached to the hub 41 as by die casting the hub directly on to the sleeve, the sleeve being provided with holes 5I through which metal of the hub may be forced.

The lower end of the hub is provided with a boss 52 preferably having a number of fiat sides, arranged, for instance, in a hexagon as shown, for receiving a wrench for holding the drum against rotation. The hub 41 may also be provided with a hole 53 in the exact center thereof which has a suitable diameter to receive the shaft 54 of a motor 55, and thebottom end of the hub may be counterbored a short distance as at 56 to receive the usual shoulder formed on the motor shaft.v In the bottom surface of the boss 52 and intersecting the center of the hub I provide a slot 51 which extends a short distance at each side of the opening and is adapted to receive a pin 58 which passes through a suitable hole in the shaft.

The hub 41 may be of suflicient length to just clear the end of the shaft 54 and may be secured in place on the shaft by means of a cap screw 59 and washer 66, the cap screw being threaded into the tapped hole 6l` in ther shaft.

If desired a pin 64 may be provided in the upper surface 49 of the flange 48 at adistance from the center corresponding to the distance of the spacing holes from the center of the plates and this pin will pass through one of the holes in the rst plate to secure it against rotation with respect to the flange and sleeve. The same arrangement lfor anchoring the plates may be used in connection with the other gure but is not absolutely necessary due to the friction between the plates and supporting flange.

After the plates have been put on the sleeve 56 and properly spaced a disc 62 is fitted over the end of the sleeve, and the upper end of the sleeve peened overthe disc as at 63. The disc 62 may have a flat lower surface to rest upon the plates while the upper surface may be tapered from a thick central portion toa thin edge corresponding to the disc`|6 and flange I1 of Fig. l.

With this construction the pin 56 may be inserted in the hole in the motor shaft provided for it and the drum'placed upon the shaft whereupon the pin will be received by the slot 51 which tends to hold it in place in the shaft `and the drum will be locked to the shaft. The cap screw 59 may be L tightened down by means of a socket wrench through the sleeve which is open at the top andif desired the boss 52 may be held with a wrench while the screw 59 is tightened.

The drum of the invention is preferably used with a linear source of light as indicated in the application above. referred to and. such a light may be positioned from the drum so that the im'- age of a portion of it will be picked up in each reflecting surface as it rotates. ner the reflecting surfaces of the plates may be perpendicular to the face thereof or in other words parallel to the axis of the drum but the arrangement may also be used with a point source of light. In this case the reflecting surfaces would have graduated angles increasing in each direction from a central plate whose surface is parallel to the axis of the drum to the uppermost and lowermost plates which may have a considerable angle with respect to the axis.

While the invention has been shown with respect to three specific line arrangements it will be evident it need not be limited to three or to the particular three arrangements selected as a standard. Other numbers of lines may be used and additional holes may be provided in each of the corners to make the plates mountable so as to scan pictures having a great Variety of line numbers.

It will be noted that inasmuch as the plates form a complete helix in one rotation the pins will be symmetrically arranged about the axis of the drum and hence the drum will be balanced Whether one or two pins are used for each pair Used in this manf of plates and regardless ofthe number of plates used for each line.

Many modications of the invention may be resorted to without departing from the spirit thereof andf-I do not therefore desire to limit myself to what has been shown and described'except as such limitations occur in the appended claims.

What I claim is:

1. A television .drum comprising a hollow sleeve, a plurality of plates each having a hole therein positioned in stacked relation upon said sleeve, the holes in said plates being of a diameter to t snugly on the sleeve, a flange on each end of said sleeve and secured to said sleeve so as to hold said plates between said ilanges, and means at each end of said sleeve to support sai-d sleeve upon a shaft.

2. A scanning drum comprising a hollow sleeve, a plurality of at plates each having a hole therein to t said sleeve positioned in stacked relation upon said sleeve, means at each end of said sleeve to hold said plates upon said sleeve, and a bearing at each end of said sleeve adapted to llt upon a motor shaft.

3. A scanning drum comprising a hollow sleeve, a plurality of flat plates each having a hole therein to t said sleeve mounted on said sleeve, a refleeting edge on each of said plates, means to space the reilecting edges of said plates in a predetermined relation around the circumference of said drum, means to hold said plates upon said sleeve so as to form a single unit, and bearing means at each end of said sleeve to receive a motor shaft.

4. A scanning drum comprising a hollow sleeve, a plurality of flat plates each having a hole therein to fit said sleeve positioned upon said sleeve, a reflecting edge on each of said plates, means to secure said plates in a predetermined relation around the circumference of said sleeve, means at the ends of said sleeve to hold said plates upon said sleeve, and means within the ends of said sleeve to receive the shaft in' concentric relation to said sleeve.

5. A scanning drum comprising a hollow sleeve, a disc rigidly secured to one end of said sleeve, a second disc rigidly secured to the opposite end of said sleeve, a plurality of said plates each having a hole therein to receive said sleeve positioned upon said sleeve between said discs, a reflecting edge on each of said plates, means to space said ,plates ina predetermined angular relation around said sleeve, and a pair of discs secured at the ends of said sleeve and having central holes therein to receive a motor shaft.

6. `A scanning drum comprising a hollow sleeve, a plurality of flat plates each having a hole therein to receive said sleeve mounted upon said sleeve in stacked relation, means at the ends of said sleeve to secure said plates in position thereon, a reiiecting edge on each of said plates, means to secure said plates so that said reflecting edges are in spaced relation aroundthe circumference of said drum, a disc positioned ateach end of said sleeve, and a plurality of fingers on. each end of said sleeve and extending over the edges of said discs to hold said discs in position, said discs having openings therein to receive a motor shaft.

'7. A scanning drum comprising a sleeve, a hub member rigidly secured to one end of said sleeve, said hub member being bored to fit over a motor shaft, a plate supporting flange integral with said hub member, a plurality of plates in stacked relation upon said sleeve and resting upon said iiange, and a disc positioned on the top of said plates and provided with a hole to fit over said sleeve, said sleeve being peene-d over said disc to hold it in position and secure said plates on said sleeve.

8. A scanning drum comprising a sleeve, means to position a plurality of plates instacked relation upon said sleeve, and means at one end of said sleeve to mount said drum upon the end of a shaft.

9. A scanning drum comprising a die cast hub member, said hub member being bored to t over a shaft, a sleeve attached to said hub member, a plate supporting flange on said hub member, a plurality of plates mounted in stacked relation upon said sleeve and resting upon said flange, an upper flange mounted on said sleeve and adapted to secure said plates upon said sleeve, and means to secure the upper flange upon the end of said sleeve.

ARNO ZILLGER. 

